Limited amounts of arable land and adverse environmental conditions, whether natural or man made, have resulted in the use for many years of closed environment structures. These have for the most part been greenhouses of the most basic type. However, over the years methods of plant husbandry and improved structures of the greenhouse type have been constantly under development.
One relatively recent advance in controlled environment husbandry has been the use of nutrient film techniques. In general terms these techniques involve the contacting of the bottom of a plant root system with a thin stream of nutrient solution. The solution soaks up through the remainder of the root system by wicking or capillary action. A great many external influences affect the relatively sensitive nutrient film technique. Efforts are now underway to control various of these influences to improve both the technical aspects and the economics of the systems.
It is in this context that the present invention arises. The physical structure for supporting plants being propagated in accordance with nutrient film techniques has hereby been substantially improved from both the technical and economic points of view. A substantial technical problem in respect of nutrient film plant propagation has been the difficulty of ensuring that the nutrient film is in more or less equal contact with all of the plants to which it is directed. This is one of a number of aspects of nutrient flow which have required improvement.
The present invention provides a system in which there is a very high likelihood that the nutrient solution will adequately contact all of the root system. In addition to achieving the desired technical improvement, this system offers substantial economic advantages over earlier systems.